The present invention is concerned with a hearing aid that makes use of the Receiver-In-Canal (RIC) concept.
A conventional behind the ear (BTE) hearing aid has a small case or housing that fits behind the ear of a hearing-impaired person, and sound is conducted to the middle ear through an ear mold that is generally customized for the wearer of the hearing aid.
Another type of conventional category of hearing aids is the in-the-ear (ITE) hearing aid, which has a housing commonly called an otoplastic, that fits into the concha with a customized fit.
More recently developed hearing aids include in the canal (ITC), mostly in canal (MIC) and completely in the canal (CIC) hearing aids. These hearing aids are quite small, and generally occupy only the bottom half of the external ear (pinna). Generally, ITC hearing aids cannot be seen when directly facing the hearing-impaired person. MIC and CIC hearing aids are even smaller, and often are not visible unless one happens to look directly into the ear of the hearing-impaired person.
A further category of hearing aids that has recently become commercially available is the open-fit or over-the-ear (OTE) hearing aid. These devices have a behind-the-ear housing or case, but it is generally much smaller than a conventional BTE housing. An open fit hearing aid usually has a thin, transparent tube that proceeds into the ear canal. This tube terminates in the ear canal with a small, resilient domed element, that is usually composed of silicone or acrylic material, and holds the tube in place. Sound is conducted into the ear canal via this tube. In a Receiver-In-Canal (RIC) design, this tube is used to carry wires that are attached to the receiver, which sits wholly in the canal.
Open-fit custom hearing aids generally have been difficult to manufacture and have performance difficulties. These designs are particularly susceptible to the “occlusion effect”, which is a plugged-up feeling experienced by the wearer in which the wearer hears his own voice as an echo. This is a major reason for hearing aid dissatisfaction and rejection. Furthermore, in known such designs, the actual sound outlet (receiver) sits in the ear canal, resulting in it getting clogged up with ear wax and resulting in hearing instrument failure necessitating repair.